If vinegar and baking soda do not successfully unclog the sink, try using hot water. Boiling water can sometimes unclog a drain. To try this method, boil a gallon of water and slowly pour it down the drain. Only do this if you have metal pipes, since PVC pipes can melt or become damaged. This will cause an even bigger mess than a clogged drain. This may create blockage or holes, forcing you to replace the sink's pipes altogether.

The second step is to cut the hole: You can complete the other steps of installing the undermount sink yourself but you may also hire a professional to cut through the granite. The hole the professional will cut will be where you insert the sink.

Before starling any plumbing work, make sure the new basin or sink fits properly. Prepare the mountings: for example, fix wall brackets, check the position of a pedestal and drill fixing holes, check the positioning of a sink unit and cut any necessary holes in it for pipes.